JPH05288977A - Motor-driven zoom lens camera with built-in electronic flash device - Google Patents

Abstract

PURPOSE:To prevent the vignetting of flash caused by the outside shape of a lens barrel at the time of flash photographing. CONSTITUTION:A lens discrimination signal (i), the information of a focal distance (f) and the information of an object distance (s) based on the outside shape of an interchangeable lens A are processed by a lens information output part 21 in a microcomputer and outputted to a camera B sides. Each information is decided by a discrimination circuit 33 through comparison circuits 31 and 32. Then, when it is discriminated that a prescribed value decided by the signal (i) is small, that means, the vignetting is caused, a zoom driving means 23 is actuated by the output of the decision circuit 33 through a lens information input part 22 and zooming correction is executed to a prescribed focal distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a correction device for performing zooming correction during flash photography in a camera with a built-in electronic flash combined with a zoom lens capable of electrically zooming.

[0002]

2. Description of the Related Art Conventionally, as a single-lens reflex camera, a camera having a built-in electronic flash has been known. In these cameras with a built-in electronic flash, there is a display indicating that charging of the flash emission has been completed or not completed, or a warning display notifying that the flash does not reach the subject, and if the shooting lens interrupts the light from the flash built in the camera. It has also been proposed that a warning or prohibition of use of the built-in flash is used.

[0003]

By the way, in the above-mentioned conventional camera with a built-in electronic flash device, when a lens is attached, the lens has a wide angle, in particular, the total length changes by zooming, and the zoom has a certain length. In the case of a lens, as shown in FIG. 5, at a certain focal length, flash light is vignetting due to the lens outline, and the vignetting is reflected on the screen, resulting in a photograph with a shadow on the screen as shown in FIG. .. Generally, in order to reduce the above-mentioned vignetting,
It is necessary to raise the position of the built-in flash of the camera and shorten the total length of the lens. However, raising the position of the built-in electronic flash device is against the trend of making cameras compact.
Also, in order to guarantee optical performance, the total length of the lens during zooming needed to be a certain length.
Various external electronic flash devices are available as cameras and accessories, but when the external electronic flash device and the mounted lens are combined, the lens outline is different at the focal length position where the flash light is at the lens and the subject distance at that time. Vignetting was sometimes created on the screen depending on the shape.

In view of the above-mentioned problems of the prior art, the present invention, in a camera with a built-in electronic flash device, shows the vignetting of the flash light on the screen due to the focal length of the mounted zoom lens and the outer shape of the lens at the object distance. To prevent
It is an object of the present invention to provide a camera that allows a photographer to mount an electric zoom lens without failure.

[0005]

In order to achieve the above-mentioned object, the present invention provides a detection lens for detecting a lens identification signal based on the lens outer shape and a focal length and a subject distance in an interchangeable lens capable of electric zooming. Means for determining the amount of vignetting due to the lens outline of the light of the flash device from the lens side identification signal and focal length information or subject distance information, or a matrix of both information, and based on the determination result The electric zoom lens is provided with zooming correction means for performing zooming correction to a predetermined value. Further, it is preferable to have warning means for giving a warning when zooming correction is applied based on the determination means and when the zoom end point on the telephoto side or the wide-angle side is reached.

[0006]

In the camera with the electric zoom lens with a built-in electronic flash device having the above-described configuration, it is determined from the identification signal on the lens side, the focal length, and the subject distance information whether or not flashing vignetting due to the lens outer shape occurs in the screen, If it is determined that vignetting will occur, zooming correction is performed up to a predetermined focal length by electric zooming, and a warning is issued when sufficient correction cannot be performed at the zoom end point, thus enabling shooting without failure.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
It will be explained based on. FIG. 1 is a sectional view of a zoom lens barrel. In the figure, reference numeral 1 is a fixed barrel that supports the first lens barrel 2 and the second lens barrel 3, and the rollers 2a and 3a projecting from the lens barrels 2 and 3 are fitted into the lens barrels 2 and 3, respectively.
The straight grooves 1a and 1b for making the vehicle go straight are cut. The first lens barrel 2 supports a first group lens L1 whose focal length is variable by its movement, and the second group lens barrel 3 supports a second group lens L2 which focuses by its movement. Reference numeral 4 denotes a zoom operation ring which rotates with respect to the fixed barrel 1. A roller 2a of the first group lens barrel 2 is fitted into the inner diameter portion of the zoom manipulation ring to cut a cam groove 4a for moving the lens barrel 2 back and forth. Reference numeral 5 denotes a cam ring rotatable with respect to the fixed barrel 1. The cam groove 5a for moving the lens barrel 3 back and forth by fitting the roller 3a of the second group lens barrel 3 and the output gear 6a of the focus motor 6 are engaged with each other. 5b. Reference numeral 7 is a rear cover attached to the fixed barrel 1, 8 is a mount attached to the rear cover 7 and mechanically connected to a camera body (not shown), 9 is a zoom brush fixed to the first lens barrel 2, and 10 is a zoom brush. A focusing brush fixed to the second group lens barrel 3, 11 is a flexible substrate having a code pattern for detecting movements of the zoom brush 9 and the focusing brush 10, and 12 is fixed to the mount 8 and is on the camera body side. Electrical contacts to electrically connect with, 13
Is a main substrate connected to the focus motor 6, the zoom motor 14, the flexible substrate 11, and the electrical contacts 12, and has an electric circuit including a microcomputer that drives the motor, outputs lens information to the camera body, and processes information from the camera body side. It is equipped with. Further, the zoom motor 14 has a gear 14 a that meshes with the zoom operation ring 4.

Regarding the operation of the lens of the zoom lens barrel having the above-described structure, in order to change the focal length, power is supplied to the zoom motor 14 and the zoom operation ring 4 is rotated to operate the roller 2a of the first group lens barrel 2. By moving along the cam groove 4a of the ring 4 and the rectilinear groove 1a of the fixed barrel 1, the first group lens L
1 moves back and forth to perform zooming, and the zooming brush 9 also moves on the code pattern of the flexible substrate 11 and outputs zooming information. On the other hand, at the time of focusing, when the cam ring 4 is rotated by the rotation of the focus motor 6, the roller 3a of the second group lens barrel 3 is moved to the cam groove 5 of the cam ring 4.
By moving along a and the straight groove 1b of the fixed barrel 1, the second group lens barrel 3 moves back and forth to perform focusing, and at the same time, the focusing brush 10 also causes the flexible substrate 11 to move.
It moves on the code pattern of and outputs focus information. Then, the output zoom information and focus information are input to the microcomputer of the main board 13, processed, and transmitted to the camera body side through the electrical contacts 12.

Next, FIG. 2 is a block diagram for operating this embodiment, in which A shows a lens barrel and B shows a camera. That is, the focal length information f and the subject distance information s are processed by the lens information output unit 21 in the microcomputer on the lens barrel A side and output to the camera B side via the electrical contacts. The respective information is the comparison circuit 3 in the camera B.
1 and 32, the magnitude is compared with a predetermined value determined by the lens identification signal i, and the information is input to the determination circuit 33,
When it is determined that the focal length f and the subject distance s are smaller than the predetermined values, the output of the determination circuit 33 is input to the lens information input unit 22 of the microcomputer on the lens barrel A side and processed to be the zoom driving means in the lens. 23 is operated to change the focal length of the zoom lens. However, when the focal length information f does not change at the zoom end point, the output of the determination circuit 33 sends a signal to the warning means 34 to issue a warning indicating vignetting.

[0010] Here, the predetermined value s _i for a given value f _i and the object distance s of the focal length f is determined by the respective lenses unique zoom type, in the case of the embodiment of Figure 1, the wide-angle side zoom When set to 1, the first group lens barrel 1 extends straight toward the subject side, and the zoom on the telephoto side, the first group lens barrel 1 extends straight toward the image plane side. In the case of such a zoom type, since the first group lens barrel 1 is extended on the wide angle side, as shown in FIG. 5, the lower light of the luminous flux emitted by the built-in electronic flash device is likely to be vignetted at the tip of the lens barrel, and FIG. The shaded area as shown in Figure 4 will come into the screen. When the limit value f _i is set as described above, it is a condition that f <f _i that a shadow is generated in the screen.

In another lens type, depending on the zoom type, the first group lens barrel moves straight when it is set to the wide-angle side and moves straight when zooming to the telephoto side.
The focal length condition at this time is that the vignetting limit value at the tip is f _i
Then, the vignetting is f> f _i . Further, as another lens type, there is a zoom type in which the first group lens barrel 1 moves in the rectilinear advance direction on the wide-angle side and the telephoto side, and becomes the shortest state in the zoom intermediate range. At this time, the vignetting limit value f _i takes two values, the limit value f _iT on the telephoto side and the limit value f _iW on the wide-angle side, and the condition of the vignetting occurrence in the comparison circuit 31 is f _iT <f <f
_iW . In this way, the conditional expression of the comparison circuit 31 is set by the lens identification signal i set by each lens.

Furthermore, for the object distance information s, in the present embodiment, when the angle of view of a certain focal length f, the vignetting shadows shown in FIG. 6 is a limit value coming into the angle of view and s _i,
The vignetting shadow becomes larger in each image as it gets closer to the short distance side than the limit value s _i . Therefore, the condition in the comparison circuit 32 is s <s _i . The vignetting limit value s _i is set by the lens identification signal i, the focal length information f, the positional condition of the lower luminous flux of the luminous flux of the built-in electronic flash of the camera body, and the like.

Next, the operation of the camera will be described with reference to the flow chart of FIG.
It will be explained based on the report. First, switch SW1 in # 1
When is turned on, a signal is sent to the lens and the
Do a circus. Then, after autofocus is completed, # 3
To perform photometry and calculate the photometric value. Then, flash at # 4
When the light emission selection switch is off, the metering described above is performed in # 17.
AV and TV are decided based on the value, and the switch is performed at # 18.
Exposure control for AV and TV determined when SW2 is turned on
Shooting is completed. Also, the switch SW2 is in the off state.
If it is in a state, return to before the photometry of # 3. On the other hand, flashing with # 4
If the selection switch is on, it means that flash is selected.
Exposure control becomes a flash emission mode.
Is determined uniformly regardless of the photometric value. And # 6
Judge whether the charging required for light emission has been completed, and
In step # 7, complete or turn off the light emission selection switch.
To warn. After charging is completed, the lens information is displayed in # 8 and # 9.
Based on the information, the focal length f and the subject distance s are set to predetermined values (here
Then f₀, S₀), The focal length f and the subject distance s are
If both are less than the specified value, zoom drive with # 10.
The focal length is corrected by zooming. The
It does not change because it is at the end of the zoom even if the zooming correction is performed.
In this case, the warning is given in # 11. Then switch with # 12
When SW2 is turned on, A is set to the value previously determined in # 13.
V, T At the same time as V is controlled, flashes occur at # 14 to # 16.
The vessel emits light, and the light emission is stopped based on the dimming of the light.
Shooting is completed. Also, when the switch SW2 is off
Return to before the photometry of # 3.

FIG. 4 shows a second embodiment of the present invention. For simplification of description, the same parts as those in the first embodiment are designated by the same reference numerals, and only different points will be described. In the present embodiment, the flash identification signal 41 of the electronic flash C attached to the camera body A is connected so as to be inputted to the discrimination circuit 33 of the camera body A. The other structure is the first described above.
It is similar to the embodiment. In this embodiment having the above configuration, the lens identification information i, the focal length information f, and the subject distance information s are processed by the lens information output unit 21 in the microcomputer on the lens barrel A side, and the lens barrel-camera It is output to the camera B side via the electrical contact. The respective pieces of information are compared in magnitude by the comparison circuits 31 and 32 in the camera B with a predetermined value determined by the lens identification signal i, and the information is judged by the judgment circuit 33.
Flash identification information 1 of the electronic flash C externally attached to the camera body B is also input to the determination circuit 33 on the camera B side by the mounting shoe with electrical contacts between the flash and camera, and the focal length f, When it is determined that the subject distance s is smaller than the predetermined value, the output of the determination circuit 33 is input to the lens information input section 22 of the microcomputer on the lens barrel A side and processed to operate the zoom drive means 23 in the lens. Then, zooming correction is performed and the focal length of the zoom lens is changed. However, when the focal length information f does not change at the zoom end point, the output of the determination circuit 33 sends a signal to the warning means 34, and a warning indicating flash vignetting is displayed.

[0015]

As described above, the present invention has a lens identifying signal based on the outer shape of the lens, a detecting means for detecting the focal length and the object distance in the interchangeable lens which can be electrically zoomed. Has a determination means for determining the amount of vignetting due to the lens outer shape of the flash light from the side identification signal and the focal length information or the subject distance information, or a matrix of both information, and based on the determination result, the electric zoom lens is zoomed to a predetermined value. With the zooming correction means, if the light flux emitted from the built-in flash unit is vignetting at the set focal length of the zoom lens, the flash will not be vignetting due to the lens outer shape in the zoom correction. It is possible to prevent the mismatch between the angle and the irradiation angle. In addition, when the zoom correction is performed by the determination unit, if the zoom end point cannot be sufficiently corrected, a warning is given, which has an effect of enabling shooting without failure.

[Brief description of drawings]

FIG. 1 is a sectional view of a lens barrel of a camera with a built-in electronic flash device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of the camera.

FIG. 3 is a flowchart illustrating the operation.

FIG. 4 is a block diagram showing a circuit configuration of a camera with a built-in electronic flash device according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of vignetting of a flash light beam by a lens barrel.

FIG. 6 is an explanatory diagram of vignetting on the screen.

[Explanation of symbols]

A ... lens barrel, B ... camera, C ... electronic flash,
L1 ... First lens group, L2 ... Second lens group, 1 ...
Fixed barrel, 2 ·· First group lens barrel, 3 ·· Second group lens barrel, 4 ·· Zoom operating ring, 5 ·· Cam ring, 6 ·· Focus motor, 8 ·· Mount, 9 ·· For zoom brush,
10 ・ ・ Focus brush, 11 ・ ・ Flexible printed circuit board, 12 ・ ・ Lens side electrical contact, 13 ・ ・ Main circuit board, 14 ・ ・ Zoom motor

Claims (2)

[Claims] 1. An interchangeable lens that can be electrically zoomed has a lens identification signal based on a lens outer shape, a detection unit for detecting a focal length and a subject distance, and further has an identification signal on the lens side and focal length information or Equipped with a determination means for determining the amount of vignetting due to the lens outer shape of the light of the electronic flash device from subject distance information or a matrix of both information, and a zooming correction means for performing zooming correction of the electric zoom lens to a predetermined value based on the determination result. A camera with an electric zoom lens with a built-in electronic flash. 2. The electronic flash device according to claim 1, further comprising warning means for warning that the zoom end points on the telephoto side and the wide-angle side are reached when zooming correction is applied based on the determination means. Camera with built-in electric zoom lens.